Many image forming apparatuses such as copying machines include a developer-storing container that supplies a developing tank with developer. Japanese Unexamined Patent Publication No. 2001-356577 (published on Dec. 26, 2001) discloses a particle-storing container in which an agitation member is taken in/out from a large aperture section disposed at the top of the inner part of the container, the agitation member is easy to mount on the main body of the container, and the agitation member is easy to take out from the container for re-use.
Japanese Unexamined Patent Publication No. 2003-337465 (published on Nov. 28, 2003) discloses a toner cartridge that is detachably mounted on an image forming apparatus. In the toner cartridge, an agitation member for agitating toner which fills the toner cartridge is slidably mounted in an axial direction. Upon insertion into the image forming apparatus, the agitation member contacts a pressing member disposed on the side close to the image forming apparatus so as to be slidden to an in-use position that is different from a not-in-use position.
Japanese Unexamined Patent Publication No. 2001-109244 (published on Apr. 20, 2001) discloses a development apparatus in which an agitation section is composed of connection sections that connects adjoining agitation members, the agitation members divided into a plurality of members along the axial direction having the same shape, and a restraint section disposed in a development container to restrain the connection section. The development apparatus rotates, upon receiving drive, to supply a development roller with developer in the development container.
FIG. 5 shows a cross section that illustrates a physical relationship between a toner cartridge 101 that is a conventional developer-storing container included in a copying-machine and a developing tank 102.
The toner cartridge 101 contains toner that has developer inside, and the toner is agitated by an agitation blade 101a. The toner cartridge 101 supplies the developing tank 102 with the toner through a supply opening 102a by using a supply roller 101b. In the developing tank 102, the supplied toner is agitated by an agitation roller 102b and is sent to an agitation roller 102c. The agitation roller 102c agitates the supplied toner and sends it to a development roller 102d. A doctor blade 102e is mounted above the development roller 102d and controls the thickness of the layer of toner on the development roller 102d. This allows the development roller 102d to supply a photoconductor 103 with a certain amount of toner. Further, a toner sensor 102f is mounted below the agitation roller 102c in the developing tank 102. The toner sensor 102f detects a residual amount of toner in the developing tank 102.
FIG. 6 shows a cross section of the toner cartridge 101 along a shaft of the photoconductor 103. The toner cartridge 101 includes a toner-storing section 111 and a waste-toner-storing section 112. A core cylinder 101d partitions space in the toner cartridge 101 such that the toner-storing section 111 and the waste-toner-storing section 112 are adjacent to each other in the direction the shaft extends (axial direction). The toner-storing section 111 is a section that stores toner to be supplied to the developing tank 102. The toner-storing section 111 includes the agitation blade 101a. The waste-toner-storing section 112 is a section that stores residual toner that was not transferred to an image in an image-forming process and was retrieved. The waste-toner-storing section 112 includes an agitation blade 101c. 
In order to assemble the agitation blade 101a and the agitation blade 101c in the housing, the core cylinder 101d is detachably mounted in the housing of the toner cartridge 101. The agitation blade 101a, the agitation blade 101c, and the core cylinder 101d are constructable and deconstructable in the housing. A bearing 101e is mounted on an end section of housing of the toner cartridge 101 that is on the side close to the toner-storing section 111. A bearing 101f is mounted on the core cylinder 101d. A bearing 101g is mounted on an end section of housing of the toner cartridge 101 that is on the side close to the waste-toner-storing section 112. The agitation blade 101a includes a flange 101h on an axial end section on the side close to the bearing 101e. The flange 101h is connected by the bearing 101e to the driving shaft system 113 that transmits driving force from the outside of the toner cartridge 101. The driving shaft system 113 includes a clutch and a gear that transmit driving force from a motor. A sponge 101j acting as a sealing member is mounted in between the flange 101h and the housing. Further, the agitation blade 101a includes a flange 101i on an axial end section on the side close to the bearing 101f. The flange 101i is connected by the bearing 101f to an axial end section of the agitation blade 101c that is on the side close to the bearing 101f. A sponge 101k acting as a sealing member is mounted in between the flange 101i and the core cylinder 101d. An axial end section of the agitation blade 101c that is on the side close to the bearing 101g is supported by the bearing 101g. This allows an axle of the agitation blade 101a and an axle of the agitation blade 101c to be connected to each other in such a way that the axles form one axle.
However, in the conventional structure of the toner cartridge 101 described above, the agitation blade 101a, the agitation blade 101c, and the core cylinder 101d are constructable and deconstructable in the housing. Accordingly, in order to absorb dimensional distortion of the members due to assembly, each member is designed in such a way that some deviation is allowed in its dimensions so as to be easily assembled. Therefore, the members are loosely interdigitated with each other. Consequently, problems may arise in which sufficient driving force for rotating the agitation blades 101a and 101c is not transmitted to the toner cartridge 101, or in which toner leaks and solidifies in a gap between the bearings 101e, 101f, and 101g and the axle.